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DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK LIFE SCIENCES LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 30 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, Dr T.V. Radhakrishnan and Dr B. K. Kulkarni, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 30 PLUS year tenure till date June 2021, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 90 Lakh plus views on dozen plus blogs, 233 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 33 lakh plus views on New Drug Approvals Blog in 233 countries...... , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc

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Novel Diacylglycerol Acyltransferase-1 (DGAT-1) Inhibitor..1-(4-(4-Amino-2-methoxy-5-oxo-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl)phenyl)cyclobutanecarbonitrile

Figure US20100197591A1-20100805-C00066


C19 H19 N5 O2

 US 20100197591

Inventores Gary E. AspnesRobert L. DowMichael J. Munchhof
Beneficiário Original Pfizer Inc





Enzyme acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the rate-limiting step in triglyceride synthesis. It has recently emerged as an attractive target for therapeutic intervention in the treatment of Type II diabetes and obesity.

It is estimated that somewhere between 34 and 61 million people in the US are obese and, in much of the developing world, incidence is increasing by about 1% per year. Obesity increases the likelihood of death from all causes by 20%, and more specifically, death from coronary artery disease and stroke are increased by 25% and 10%, respectively. Key priorities of anti-obesity treatments are to reduce food intake and/or hyperlipidemia. Since the latter has been suggested to provoke insulin resistance, molecules developed to prevent the accumulation of triglyceride would not only reduce obesity but they would also have the additional effect of reducing insulin resistance, a primary factor contributing to the development of diabetes. The therapeutic activity of leptin agonists has come under scrutiny through their potential to reduce food intake and, also, to reverse insulin resistance; however, their potential may be compromised by leptin-resistance, a characteristic of obesity. Acyl coenzyme A:diacylglycerol acyltransferase 1 (DGAT-1) is one of two known DGAT enzymes that catalyze the final step in mammalian triglyceride synthesis and an enzyme that is tightly implicated in both the development of obesity and insulin resistance. DGAT-1 deficient mice are resistant to diet-induced obesity through a mechanism involving increased energy expenditure. US researchers have now shown that these mice have decreased levels of tissue triglycerides, as well as increased sensitivity to insulin and to leptin. Importantly, DGAT-1 deficiency protects against insulin resistance and obesity in agouti yellow mice, a model of severe leptin resistance. Thus, DGAT-1 may represent a useful target for the treatment of insulin and leptin resistance and hence human obesity and diabetes. Chen, H. C., et al., J Clin Invest, 109(8), 1049-55 (2002).

Although studies show that DGAT-1 inhibition is useful for treating obesity and diabetes, there remains a need for DGAT-1 inhibitors that have efficacy for the treatment of metabolic disorders (e.g., obesity, Type 2 diabetes, and insulin resistance syndrome (also referred to as “metabolic syndrome”)).






 US 20100197591

Figure US20100197591A1-20100805-C00008

Scheme II outlines the general procedures one could use to provide compounds of the general Formula (II).

Figure US20100197591A1-20100805-C00009
Figure US20100197591A1-20100805-C00010

Scheme IV outlines a general procedure for the preparation of compounds of the general Formula VI.


Figure US20100197591A1-20100805-C00011



Figure US20100197591A1-20100805-C00066


1-[4-(4-amino-2-methoxy-5-oxo-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl)phenyl]cyclobutanecarbonitrilePotassium nitrate (7.88 g, 77.0 mmol) was suspended in sulfuric acid (45 mL) at 0° C. and stirred for 30 minutes until a clear and colorless solution was obtained (NOTE—a blast shield is highly recommended). An addition funnel was charged with 1-phenylcyclobutanecarbonitrile (11.40 g, 72.5 mmol), and this neat starting material was added drop wise at such a rate that the internal reaction temperature did not exceed 10° C. Upon completion of the addition (which required 90 min), the mixture was poured onto 300 g of ice and stirred vigorously for 30 minutes. The resulting suspension was filtered, and the solid was washed with water and dried under vacuum to afford give 1-(4-nitrophenyl)cyclobutanecarbonitrile (13.53 g, 92%) as a light tan powder.

1H NMR (500 MHz, CHLOROFORM-d) δ ppm 2.11-2.21 (m, 1H) 2.47-2.58 (m, 1H) 2.66 (s, 2H) 2.88-2.96 (m, 2H) 7.63 (d, J=8.54 Hz, 2H) 8.29 (d, J=8.54 Hz, 2H).

A steel hydrogenation vessel was loaded with 1-(4-nitrophenyl)cyclobutanecarbonitrile (103.6 g, 0.51 mol), 10% palladium on activated carbon (10.3 g; contains ˜50% of water), and 2-methyltetrahydrofuran (1.3 L). The mixture was stirred under 30 psi of hydrogen gas at 45° C. for 4 h. The mixture was filtered through a pad of celite and filtrate concentrated. Heptane (1 L) was added to the obtained oil and the heterogeneous mixture was stirred while slowly cooled to room temperature, causing the product aniline to solidify. The solid was filtered off and dried in vacuum to give 1-(4-aminophenyl)cyclobutanecarbonitrile (86.6 g, 98%).

1H NMR (CHLOROFORM-d) δ ppm 7.12-7.25 (m, 2H), 6.61-6.76 (m, 2H), 3.68 (br. s., 2H), 2.68-2.88 (m, 2H), 2.48-2.64 (m, 2H), 2.30-2.45 (m, 1H), 1.94-2.14 (m, 1H)

A mixture of 1-(4-aminophenyl)cyclobutanecarbonitrile (42.2 g, 245 mmol), triethylamine (27.1 mL, 394 mmol), and ethyl acrylate (28.0 mL, 258 mmol) were combined in ethanol (27 mL) and heated to reflux for 24 hours. The mixture was concentrated to dryness and toluene (600 mL) added and concentrated to dryness to give ethyl N-[4-(1-cyanocyclobutyl)phenyl]beta-alaninate as brown oil, which was used without further purification.

1H NMR (CHLOROFORM-d) δ ppm 7.22 (d, 2H), 6.63 (d, 2H), 4.12-4.21 (m, 3H), 3.47 (q, J=6.3 Hz, 2H), 2.74-2.83 (m, 2H), 2.53-2.66 (m, 4H), 2.33-2.45 (m, 1H), 2.00-2.11 (m, 1H), 1.28 (t, 3H)

Ethyl N-[4-(1-cyanocyclobutyl)phenyl]-beta-alaninate was combined with cyanoacetic acid (22.9 g, 270 mmol) and 4-dimethylaminopyridine (2.30 g, 18.8 mmol) in N,N-dimethylformamide (400 mL) and cooled to 0° C. Diisopropylcarbodiimide (41.7 mL, 270 mmol) was then added drop wise over 30 minutes. Once addition was complete, the reaction was slowly warmed up to room temperature and stirred for 16 hours. Reaction was then poured into saturated aqueous sodium bicarbonate (600 mL) and stirred for 30 mintues. Ethyl acetate (1 L) was added and the mixture was filtered to remove the insoluble diisopropylurea. The phases of the filtrate were separated, and the organic phase was washed with brine and dried over sodium sulfate and concentrated to give ethyl N-(cyanoacetyl)-N-[4-(1-cyanocyclobutyl)phenyl]-beta-alaninate as yellow oil that was used with out further purification in the following step.

ethyl N-(cyanoacetyl)-N-[4-(1-cyanocyclobutyl)phenyl]-beta-alaninate and 1,8-diazabicyclo[5.4.0]undec-7-ene (350 mmol) were combined in methanol (400 mL) and heated to 70° C. for 30 minutes. The mixture was concentrated to dryness then partitioned between water (400 mL) and 2:1 ethyl acetate:heptane (400 mL). The aqueous phase was separated and acidified to pH 2 by the addition of 1M hydrochloric acid (400 mL). The precipitate was filtered off and washed with water (300 mL) and 2:1 ethyl acetate:heptane (300 mL) give 1-(4-(1-cyanocyclobutyl)phenyl)-4-hydroxy-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (31.7 g, 44% over 3 steps) as an off-white solid.

1H NMR (DMSO-d6) δ ppm 7.39-7.45 (m, 2H), 7.31 (d, 2H), 3.78 (t, J=6.7 Hz, 2H), 2.79 (t, 2H), 2.66-2.75 (m, 2H), 2.53-2.64 (m, 2H), 2.16-2.31 (m, 1H), 1.91-2.04 (m, 1H)

m/z (M+1)=294.4

1-(4-(1-Cyanocyclobutyl)phenyl)-4-hydroxy-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (50.0 g, 170 mmol) and N,N-dimethylformamide (0.66 mL, 8.5 mmol) in dichloromethane (350 mL) was cooled to 0° C. Oxalyl chloride (18.0 mL, 203 mmol) was added over 15 minutes. The mixture was warmed to room temperature over 2 hours. Methanol (300 mL) was then added as a steady stream, and the mixture was heated at 45° C. for 16 hours. The mixture was cooled to room temperature and concentrated to get rid of most of the dichloromethane. Methanol (200 mL) was added and the thick slurry was stirred for 2 hours. The solid was filtered and dried under vacuum to give 1-(4-(1-cyanocyclobutyl)phenyl)-4-methoxy-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (48.3 g, 92%) as an off-white powder.

1H NMR (400 MHz, DMSO-d6) δ ppm 1.91-2.03 (m, 1H) 2.18-2.31 (m, 1H) 2.54-2.63 (m, 2H) 2.67-2.75 (m, 2H) 3.03 (t, J=6.73 Hz, 2H) 3.85 (t, J=6.73 Hz, 2H) 4.01 (s, 3H) 7.33 (d, J=8.78 Hz, 2H) 7.44 (d, J=8.78 Hz, 2H)

m/z (M+1)=308.4

1-(4-(1-Cyanocyclobutyl)phenyl)-4-methoxy-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (12.04 g, 37.9 mmol) and cyanamide (1.64 g, 41.0 mmol) were suspended in methanol (200 mL) at room temperature. A solution of 25% sodium methoxide in methanol (45.0 mmol) was then added drop wise over 10 minutes to obtain a clear homogeneous solution of the intermediate cyanamide adduct. In one portion, sulfuric acid (5.06 mL, 94.9 mmol) was added, and the mixture was heated to 50° C. for 16 hours. The mixture was then cooled to room temperature and basified to pH 10-11 by the addition of 1N sodium hydroxide, and the thick suspension was stirred for 20 minutes. The solid was filtered, washed with cold methanol and water, and dried under vacuum to obtain the crude product as a mixture contaminated with the vinylogous amide (4-amino-1-[4-(1-cyanocyclobutyl)phenyl]-2-oxo-1,2,5,6-tetrahydropyridine-3-carbonitrile). This solid mixture was heated to reflux in methanol (150 mL) for 3 hours then cooled to room temperature and filtered. The solid collected was then dissolved in a minimal amount of acetic acid (30 mL) at 60° C. to obtain a clear yellow solution. Water was then added drop wise at 60° C. until the cloudiness persisted, and the mixture was allowed to return to room temperature. Another 50 mL of water was added and the fine suspension was filtered, washed with water, and dried under vacuum to afford the title compound (4A) (6.80 g, 51%) as a light yellow solid.

1H NMR (500 MHz, DMSO-d6) δ ppm 1.97-2.06 (m, 1H) 2.23-2.34 (m, 1H) 2.59-2.67 (m, 2H) 2.71-2.79 (m, 2H) 2.96 (t, J=6.71 Hz, 2H) 3.86 (s, 3H) 3.91 (t, J=6.71 Hz, 2H) 7.39-7.44 (d, J=8.54, 2H) 7.47-7.51 (d, J=8.54, 2H) 7.81 (br. s., 1H) 8.35 (br. s., 1H).

m/z (M+1)=350.4




Org. Process Res. Dev.201317 (12), pp 1510–1516
DOI: 10.1021/op400215h
Abstract Image
A practical large-scale synthesis was developed for 1, a DGAT-1 inhibitor, involving an aza-Michael reaction, amidation, Dieckman cyclization, and conjugate addition of cyanamide followed by cyclization, to form the fused 4-amino-7,8-dihydropyrido[4,3-d]pyrimidin-5-one scaffold. The enabled process presented here substantially improved safety (in particular, due to eliminating a nitration step and optimizing a high-energy intermediate step), reproducibility, and scalability, resulting in delivery of a multikilogram quantity of the API with high purity. The controls of API quality and particle size were also discussed.
Purification of Crude 1-(4-(4-Amino-2-methoxy-5-oxo-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl)phenyl)cyclobutanecarbonitrile (1)
 compound 1 as a white powder (2.61 kg, 51.8%). HPLC purity was 99.63%, associated with 0.16% of 14 and 0.13% of 15. Particle Size: D[4, 3] = 25 μm, D[v, 0.95] = 58 μm. Residual Solvents: acetic acid 0.4 wt %, water 0.1 wt % and DMF <0.1 wt %.
1H NMR (DMSO-d6) δ 1.93–2.05 (m, 1H), 2.18–2.32 (m, 1H), 2.55–2.65 (m, 2H), 2.68–2.77 (m, 2H), 2.93 (t, J = 6.7 Hz, 2H), 3.83 (s, 3H), 3.88 (t, J = 6.7 Hz, 2H), 7.39 (d, J = 8.6 Hz, 2H), 7.46 (d, J = 8.6 Hz, 2H), 7.78 (d, J = 3.9 Hz, 1H), 8.32 (d, J = 3.9 Hz, 1H).
13C NMR (DMSO-d6) δ 17.5, 31.4, 34.6, 47.5, 54.9, 98.8, 125.0, 126.6, 126.7, 137.7, 142.8, 164.9, 165.3, 165.9, 171.0;
HRMS (m/z): calculated for C19H19N5O2, [M + H]+ 350.1612; found 350.1620.
Elemental analysis: calculated for C19H19N5O2: C 65.32, H 5.48, N 20.04; found: C 65.40, H 5.45, N 20.16.
Liquid chromatography mass spectrometry (LCMS) was performed on an Agilent 1100 Series (Waters Atlantis C18 column, 4.6 mm × 50 mm, 5 μm; 95% water/acetonitrile linear gradient to 5% water/acetonitrile over 4 min, hold at 5% water/acetonitrile to 5 min, trifluoroacetic acid modifier (0.05%); flow rate = 2.0 mL/min). Reaction monitoring and purity of intermediates and the final compound were checked by HPLC in the following conditions: Column: Zorbax SB-CN, 5 μm, 4.6 mm × 150 mm; Column Temperature: 30 °C; Flow Rate: 2 mL/min; Detection: UV @ 210 nm; Mobile phase: A: 0.2% phosphoric acid in water, B: Acetonitrile; Linear Gradient: from 95% of A to 5% of A within 15 min. HPLC purity was reported at 210 nm wavelength.
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